When applications are created, each one has their own folder. Thus to run the application, it would be my_app/my_app.php
But the folder does not have a default index file. Therefore, online I can go to the my_app/ folder and can see all the files associated with that application.
What is needed is a default index that will at least forward to the application’s main php file.
my_app/index.php -> my_app/my_app.php